Synchronizer for clocks



(No Model.) 3 SheetsSheet 2.

H. S. PRENTISS. SYNGHRONIZER FOR CLOCKS.

WITNESSES INVENTOB I ,luw/i W J'Lentg SPtenhss BY A (No Model.) 3Sheets-Sheet 37 H. S. PRENTISS..

SYNGHRONIZER FOR CLOCKS.

No. 533,919. Patented Feb. 12,1895.

11 9. Fa s.

WITNESSES: INVENTOR: 1451M flQfWW/Zfl' Henry S. Ptenciss,

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UNITED STATES PATENT OFFICE.

HENRY S. PRENTISS, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE PRENTISSCLOCK IMPROVEMENT COMPANY, OF NEIV YORK, N. Y., AND JERSEY CITY, NEWJERSEY.

SYNCHRIONIZER FOR CLOCKS.

SPECIFICATION forming part of Letters Patent N 0. 533,919, datedFebruary 12, 1895. Application filed June 30,1 892. Renewed June 22,1894. Serial No.5l5, l25. (No model.)

To all whom it may concern.-

Be it known that I, HENRY S. PRENTISS, a citizen of the United States,and a resident of Elizabeth, in the county of Union and State of NewJersey, have invented certain new and useful Improvements inSynchron-izers for glocks, of which the following is a specificaion.

My invention has reference to electrically synchronizing clocks havingself contained motors, and it consists in certain novel features,whereby slow running clocks are advanced to the correct time at thecommencement of the synchronizing period, and fast running clocks areheld at the hour, until the exact hour as indicated by the master clockis reached, or until the end of the synchronizing period; all of whichis more fully pointed out in the following specification and claims, andillustrated in the accompanying drawings, in which Figure 1 represents aface View, part being broken away, of a secondary clock. Fig 2 is avertical section in the plane 00 to, Fig. 1. Fig. 3 is a diagram showingthe arrangement of the clocks in a system. Figs. 4: to 9 are detailviews on a larger scale than the preceding figures, illustrating detailparts and their operation.

Similar letters indicate corresponding parts throughout the severalviews.

In these drawings the letter C designates one of the secondary clocks,which may embody any suitable motor and movement. In this example, Ihave illustrated a pendulum movement, in which an is the arbor of theminute hand; P, the pendulum; V, the verge rod; 19, the pallet levermounted on an arbor 19, and S, the scape wheel mounted on an arborj.

In line with the arbor j, (see Figs. a to 9 especially) and supportingone end thereof, is arranged a stud j, on which is mounted a pinion gwhich is adapted to slide back and forth thereon, and meshes with one ofthe gears of the train. The pinion carries a dog a b, one end a of whichis provided with a tooth a, normally adapted to engage with one of theteeth of the scape-wheel S for propelling the same. The opposite end I)of the dog is arranged to be engaged, under certain circumstances, by adetent c secured to the frame of the clock. The pinion g is engaged by aforked arm g mounted on a bar g which is guided to move in the directionof its length and is connected to the arm-aturef of an electromagnet M.A spring it normally draws the pinion toward the scape-Wheel, its motionbeing arrested by a suitable shoulder on the bar g Consequently thetooth of the dog CL 1) is in engagement with the scape-wheel S, and theconnection between the latter and the train of the clock motor isestablished. The detent c is so arranged with respect to the end I) ofthe dog, that when the secondary clock is at the hour, the said end I)is quite opposite the said detent.

In the example illustrated, I have made use of a scape-wheel which makesone rotation a minute. Consequently at the end of each minute the end I)of the dog is opposite the detent c.

D is a circuit closer, of any suitable construction, but which I havehere shown as consisting of a cam-shaped metallic part (I mounted. onthe arbor m of the minute hand,

and a part d in the shape of a spring contact arm. Back of this circuitcloser islocated a second circuit closer E, consisting of a metalliccam-shaped part c mounted on the arbor m; a part e made of insulatingmaterial,

a portion of which projects above the surface of the part c; and acontact arm 6 The circuit closer D is intended to close the circuit incase the secondary clock is slow, and to that end is so set, that thecircuit is closed by the same at a short time, say two minutes beforethe hour as indicated by the secondary clock, and then broken at oneminute before the hour as indicated by said clock. The circuitcloser Eis intended to close the circuit in case the secondary clock is fast,and to this end it is so set, that the contact arm (2 leaves theinsulated part c, and consequently closes the circuit at the hour asindicated by said secondary clock and then breaks the circuit shortlyafter.

The master clock closes the circuit at one minute before the hour,(exact hour,) and breaks it at the exact hour.

It will be readily understood that when the secondary clock is correct,no effect is protoo I duced on the same by the making and breaking ofthe circuit at the master clock.

Assuming the case that one 'of the secondary clocks is slow, it will beseen that the circuit is not broken by the circuit closer D, at a minutebefore the exact hour. Conse quently, when the circuit is closed by themaster clock at one minute before the exact hour, the electro-magnet Mis vitalized and the dog a b is withdrawn from engagement with thescape-wheel S, and the train is free to move until its motion isarrested by the engagement of part b of the dog with the detent c, whichtakes place at one minute before the hour, and the hands of thesecondary clock indicate this time. The circuit is then broken at D andthe clock continues in the usual manner.

Assuming the case that one of the secondary clocks is fast,(the errornot to exceed one minute)it will be seen that the circuit is closed at Eat a corresponding time before the exact hour, that is to say, it isclosed at the hour as indicated by the secondary clock. The circuit atthe master clock being closed at one minute of the hour, as beforestated, the dog a b is withdrawn as soon as the secondary clockindicates the hour, but, in view of the fact that at that time the endI) of the dog is quite opposite the detent, the train is not permittedto advance, and the clock simply remains idle. The circuit being brokenby the master clock at the exact hour, the connection of the train withthe scape-wheel is reestablished and the clock resumes its motion atthat time.

In Fig. 3 I have shown the clocks arranged in a system, A beingthemaster clock; D,1ts circuit closer; O 0 G the several secondary clocks;B, the battery; 10 and 11, the line wires, and I2, 13 and 14s, theseveral local wires.

Instead of bringing the slow running secondary clock to the correct timeat the commencement of the synchronizing period, they may be setslightly in advance of the correct time at this time; then permitted torun in the usual manner, then held until the exact hour, and thenreleased. To this end the circuit closer I), as before, closes thecircuit at two minutes before the hour as indicated by the secondaryclock, and breaks it at one minute before the hour, but the masterclock, instead of closing the circuit at one minute before the exacthour, closes it at, say, sixty-five seconds (more or less) before thehour, so that, as it were, the time at which the master clock closes thecircuit overlaps the time during which the circuit closer at thesecondary clock is closed. Assuming the case that the secondary clock iscorrect, it will be seen, that the circuit is closed at D two minutesbefore the exact hour. The master clock closes the circuit at sixty-fiveseconds of the exact hour, and consequently the secondary clock is ad"vanced to within one minute of the hour, at which time the circuitisbroken at E and the clock again runs as usual, but is actually fiveseconds fast. Then the secondary clock reaches the hour, as indicated bythe same, the circuit closer E closes the circuit and the clock is heldat the hour until the circuit is broken at the master clock, at theexact hour. When the secondary clock is slow a like action takes place.

I do not herein wish to restrict myself to any particular means forestablishing the connection between the governing member and the train,nor to the application thereof directly to the scape-wheel. Neither doIwish to restrict myself to the duration of the synchronizing periods ashere stated, since these will vary with the part of the train to whichthe connecting device is applied, as well as with the number of timesthat the clocks are synchronized daily. Neither do I wish to restrictmyself to the use of circuit closers, in

preference to mechanical means, or to their application to the arbor ofthe minute hand, as they could be operated by a faster moving part, andbrought into action only at the synchronizing period.

IVhat I claim as new,and desire to secure by Letters Patent, is-- 1. Ina clock system, the combination of a master clock constructed to closethe circuit at a predetermined period before the hour and to break it atthe hour, and a secondary clock provided with a separable connectionbetween two operativeparts of the train, an electro-magnet controllingsaid connection, a detent for arresting the movement of the train whenin a predetermined position, and a circuit closer D operated by thetrain and set to close the circuit through the electro-magnet in advanceof the closing of the circuit at the master clock, and to break itsimultaneously with the closing of the circuit at the master clock,substantially as described.

2. In a clock system, the combination of a master clock constructed toclose the circuit at apredetermined period before the hour and to breakit at the hour, and a secondary clock provided with. a separableconnection between two operative parts of the train, an electro-magnetcontrolling said connection, a detent forarresting the movement of thetrain when in a predetermined position and two circuit closers operatedby the train; the one being set to close the circuit through theelectro-magnet in advance of the closing of the circuit at the masterclock, and to break it simultaneously with the closing of the circuit atthe master clock; the second circuit closer being set to close thecircuit through the electro-magnet at the hour as indicated by thesecondary clock, substantially as described.

In testimony that I claim the foregoing as my invention I have signedmynarne, in presence of two witnesses, this ant day of June, 1892.

HENRY S. PRENTISS.

Witnesses:

A. FABER DU FAUR, .ln, KLAS H. TEnUs'rUn.

IIO

